Deep vein thrombosis (DVT) occurs when a clot (thrombus) forms within a vein and completely or partially occludes it, blocking or restricting blood flow in that vessel.
In principle, any deep vein of medium or large caliber can be affected by TEP, but generally those most affected are the veins in the legs or those in the arm, neck, or found in the abdomen.
TEP is an acute event that needs to be managed appropriately in a timely manner, both to limit the discomfort associated with the interruption of blood flow locally and, more importantly, to avert the development of pulmonary embolism: its most severe and potentially fatal complication, brought about by the detachment and entry into the general bloodstream of a thrombus fragment that, upon reaching the lungs, can block part of the pulmonary circulation.
PTE can affect people of any age, especially those who are predisposed, undergoing abdominal or orthopedic surgery, or forced into prolonged immobility, but it tends to be more common among the elderly (especially, if they move little).